Removed the calling of suicide() when disconnected() was called by the driver

I don't think that ```suicide()``` should be called in the case of a disconnected event. As this will be called when the driver detects a disconnection from the master. When a new master is detected  ```registered()``` is called by the driver and Marathon continues happily along its way.

I noticed these issues because Marathon was committing suicide when there were long running network issues between Marathon and the Mesos master.

All I did with this commit is remove the ```suicide()``` call and added a little documentation from the Mesos docs.